CREATING YOUR RAIN GARDEN Photo Credit: Rutgers Cooperative Extension WRITTEN BY HTTP://WWW.WIKIHOW.COM/ CREATE-A-RAIN-GARDEN CREATING YOUR RAIN GARDEN Contents Why Rain Gardens? ....................................................................................................................................................... 2 How to Create a Rain Garden ........................................................................................................................................ 3 1. Find a suitable location for your garden ........................................................................................................................ 4 2. Figure out How Big Your Rain Garden Should Be .......................................................................................................... 6 3. Plot Out the Garden Plan ............................................................................................................................................... 8 4. Stake out the Garden Area ............................................................................................................................................ 8 5. Determine How Deep Your Garden Should Be .............................................................................................................. 9 6. Dig Out the Garden to the Desired Depth ................................................................................................................... 10 7. Add Some Compost ..................................................................................................................................................... 12 8. Level the Bottom of Your Basin ................................................................................................................................... 13 9. Build a Berm to Hold the Water In .............................................................................................................................. 14 10. Plant an Assortment of Perennial Plants in the Garden .............................................................................................. 15 11.. Add a Layer of Mulch ................................................................................................................................................... 17 . 12. Plant a ground cover or grass on the berm. ................................................................................................................ 18 13.. Water the Plants .......................................................................................................................................................... 18 . 14. Control Weeds ............................................................................................................................................................. 19 . Tips .............................................................................................................................................................................. 20 Warnings ...................................................................................................................................................................... 22 Examples ...................................................................................................................................................................... 23 Plant Guide .................................................................................................................................................................. 25 Base ............................................................................................................................................................................. 26 Slope ............................................................................................................................................................................ 28 Buffer ........................................................................................................................................................................... 30 Other Plants ................................................................................................................................................................. 32 Resources..................................................................................................................................................................... 34 1 | P a g e CREATING YOUR RAIN GARDEN WHY RAIN GARDENS? The rain falling on buildings and pavement in suburban and urban areas turns into “run off” that rapidly reaches rivers and streams. There it can flood roads and buildings, erode stream banks, and carry pollutants damaging to human health and aquatic life. Homeowners and businesses can help reduce these negative impacts by slowing down and soaking up the runoff flowing off of their roof tops and paved surfaces. One effective and attractive way to do this is to create a rain garden. This Creating Your Rain Garden booklet tells you how to proceed with the planning, installation, and care of a rain garden. The 14 Create-A-Rain-Garden steps and following two sections on Tips and Warnings come directly from wikiHow to do anything at Wikihow.com/Create-A-Rain-Garden (Edited by Waited, Sondra C, Eric, Travis Derouin and 18 others). We added the Plant Guide to provide more direction on what to plant in a rain garden in SE Pennsylvania. We also included lists of additional guidance documents and local contacts for more information on rain gardens. We invite you to help keep our water clean and our streams healthy by creating a rain garden! The Pennsylvania Environmental Council 2 | P a g e CREATING YOUR RAIN GARDEN HOW TO CREATE A RAIN GARDEN There are lots of ways you can reduce water pollution, but rain gardens may be the most beautiful of them. A rain garden is like a bowl or basin in your yard that captures rainwater from your roof, sidewalks, and driveways, and allows it to soak into the soil instead of polluting local watersheds as stormwater runoff. As an added bonus, since rain gardens are planted with an assortment of native plants, they make an attractive, low-maintenance addition to your yard. Downspout discharging roof runoff to yard or rain garden Rain garden plants filtering runoff Root “sponge” zone Storm sewer pipe discharging to stream Runoff from driveways & or river roads carrying nonpoint source pollution Image Courtesy of the City of Maplewood, MN 3 | P a g e CREATING YOUR RAIN GARDEN FIND A SUITABLE LOCATION FOR YOUR GARDEN It's easiest to install a rain garden in an area of your yard that water already flows to, usually a depression in the ground or a spot at the bottom of a slope. you can usually identify a suitable area by examining your yard during a rain storm to see how water flows off it. Rain gardens should be located at least 10 feet away from foundations to prevent basement flooding and structural problems. o They should never be located directly over a septic system, over underground utility lines--always call before you dig--or in a right-of-way. o In addition, rain gardens are not suitable for areas where the seasonal high water table level is less than 24" from the surface, as the water table will prevent infiltration of runoff water into the soil. o Finally, large rain gardens, or any rain garden that requires extensive excavation, should generally not be placed under large trees, as excavation may damage tree roots and excessive water can be harmful to some species of trees. 4 | P a g e CREATING YOUR RAIN GARDEN The more level the spot, the easier it will be to install your rain garden. The rain garden site doesn't have to be perfectly level, but steeper slopes will require more excavation to make your garden deep enough to hold water, and slopes over 12% generally require too much excavation to be worthwhile. A spot at the base of a steep slope is best. The most obvious spot for a rain garden is an area where water already tends to pool after rains. Pooling or ponding, however, may indicate that the water table is too high or, more commonly, that the soil has a low infiltration rate, which will make the area unsuitable for a rain garden. o To test for adequate drainage, dig a hole 6-8" deep and fill it with water. The water should drain completely within 12 hours; if it doesn't, the spot is not suitable for a rain garden unless you do some extra work to prepare the soil (see Tips section). 5 | P a g e CREATING YOUR RAIN GARDEN FIGURE OUT HOW BIG YOUR RAIN GARDEN SHOULD BE The ideal size of your rain garden depends on the size of the area that drains into it and the soil in the rain garden. Determine the area (in square feet or square meters) of the surface that will drain into your rain garden. o Watch the drainage pattern during a storm or carefully examine the contours of your yard to determine where the water will come from. o Then measure this, including, if applicable, the area of your roof and any paved surfaces that will drain into the garden. The area of your rain garden should be proportional to the area it drains. o For sandy soils, the rain garden size should equal about 10-20% of the total drainage area, while for very clayey soils, aim to make your rain garden equal to 50-60% of the total drainage area. 6 | P a g e CREATING YOUR RAIN GARDEN o Loamy soils require a rain garden area somewhere in between these two extremes, depending on their clay content. These proportions can be reduced for deeper rain gardens (those which